On the Qafoo blog today there's a new article talking about testing the one thing that we as developers can fear the most - legacy code.

Today we know about the benefits of Test Driven Development and normally also start new projects using TDD. Most projects from the last couple of years integrated this method in their daily development process, which often results in in good code coverage results of 90% and above. But what about all the other old projects, you still manage in your daily work?

They offer three possible solutions to the problem with the third being their recommended option - adding tests to the code as we have to change it. This can still lead to a code base with less than ideal coverage numbers so they've developed a new tool, PHP_ChangeCoverage, that creates a new kind of report based on a timeframe rather than an overall codebase coerage. You can see an example of the report here (versus this). Installation instructions are also included.